Heater with combustion chamber located below fluid distributing means

ABSTRACT

Liquid to be heated is introduced into the top of a column and distributed in downward flow through the column. A combustion chamber is disposed within the column and has a closed top and closed side walls, and an open bottom. Combustion gases produced by a burner in the combustion chamber are constrained to flow through the open bottom of the chamber and then upwardly through an annular space between the chamber and column whereat the gases commence to contact the downflowing liquid. The spent gases are discharged at the top of the column and the heated liquid at the bottom of the column.

United States Patent Bougard 5] Mar. id, 11972 [72] Inventor: JacquesBougard, Monceau-sur-Sambre,

Belgium [73] Assignee: Ateliers J. Ilaurez Societe Anouyme,Monceau-sur-Sambre, Belgium [22 Filed: Dec. 15,1969

211 Appl.No.: 885,192

FOREIGN PATENTS OR APPLICATIONS 87,189 6/1896 Germany ..l26/359 7,0311905 Great Britain 126/359 26,524 1905 Great Britain l 26/359 PrimaryExaminer-Frederick L. Matteson Assistant ExaminerRobert A. DuaAttorney-Waters, Roditi, Schwartz 8L Nissen [5 7] ABSTRACT Liquid to beheated is introduced into the top of a column and distributed indownward flow through the column. A combustion chamber is disposedwithin the column and has a closed top and closed side walls, and anopen bottom. Combustion gases produced by a burner in the combustionchamber are constrained to flow through the open bottom of the chamberand then upwardly through an annular space between the chamber andcolumn whereat the gases commence to contact the downflowing liquid. Thespent gases are discharged at the top of the column and the heatedliquid at the bottom of the column.

1 Claim, 1 Drawing Figure HEATER WITH COMBUSTION CHAMBER LOCATED BELOWFLUID DISTRIBUTING MEANS The present invention relates to the provisionof a heater of the type comprising, in a column, a combustion chambersituated below a space equipped with fluid-distributing means, in whichspace the fluids meet in countercurrent, the heated liquid descendingfrom one end and the combustion gases rising from the other.

In known heaters of the above type, the combustion chamber is open atthe top, which means that the extremely hot gases leaving these chambersdo not meet the liquid to be heated until they reach the spacecontaining the distributing elements or, at best, meet the liquid only ashort distance beneath these elements. Consequently, the grid supportingthe distributing elements, and the elements themselves, are subjected torapid corrosion and scaling, caused by the extremely hot combustionproducts which may be at a temperature of the order of 1,000 C.Moreover, since the transfer of heat from the gases to the liquid takesplace substantially within the space containing the distributingelements, this space must be quite large and takes up a great part ofthe column.

By the present invention there is provided heating apparatus including acombustion chamber having an opening in its underside, and an enclosedupper side, the combustion chamber enclosing a burner, there beingprovided means to distribute a liquid over the upper side of thecombustion chamber, and means to collect the heated liquid beneath thechamber.

The combustion chamber may be positioned in a column, and the means todistribute the liquid may include a distributing element or elementspositioned above the combustion chamber.

The burner may be aligned horizontally in the upper portion of thecombustion chamber. The distributing means may include a distributingtray positioned above the distributing element or elements.

The sole FIGURE of the accompanying drawing, given only by way ofexample, diagrammatically shows in side elevation view one embodiment ofthe invention.

The apparatus comprises, in a column 1 of a circular or rectangularcross section a combustion chamber 2 which has the shape of a bellclosed on top and arranged below a grid 3 which supports distributingelements occupying the space 4. Above this space is arranged a tray 5having a perforated bottom into which tray is connected a conduit 6 forfeeding liquid to be heated. At the top of the column is provided a pipe7 for evacuating the cooled combustion products towards the flue, and inthe lower part of the column is provided a space 8 from which the liquidwhen heated is discharged via a conduit 9 towards the point ofutilization. Near the top of the bell 2 is arranged a burner I inhorizontal position to which burner fuel is fed through a conduit 11,and combustion air from a blower 12.

Liquid introduced through the conduit 6 spreads over the tray and,leaving the latter through the perforated bottom is distributed over thewhole cross section of the space 4 which contains the distributingelements. The liquid meets combustion products in the space 4, in acountercurrent flow after the latter have already been cooled to aconsiderable extent. After having passed through the grid 3, part of thefinely dispersed liquid descends upon the bell 2, thereafter to trickledown through the annular space 13 thus remaining constantly in directcontact with the combustion products which are rising through theannular space 13. The hot liquid collects in the space 8 below thecombustion chamber and leaves the column through the conduit 9.

The combustion products produced in the bell 2 have a temperature of theorder of l,000 C. when they clear the lower border of the bell, and theydo so with great turbulence. The

combustion products immediately start to surrender a large part of theirheat to the liquid, both by radiation and by direct contact with theliquid descending in dispersed form, so that, at a point just above thelower part of the annular space U, the temperature of the combustiongases will have been reduced considerably, down to a point at which theyno longer cause COITOSIOII or scaling. Because of this abrupt drop IIltemperature, the volume of the gases is also reduced considerably, andthis enables them to rise in the annular space and in the spacecomprising the distributing elements without carrying with themdescending liquid.

For example, in a heater having a capacitor of l60,000 cal./h., and usedfor heating water that enters through the conduit 6 at 10 C. to atemperature of C., it was found that the temperature in the annularspace 13, a little above the lower end of this space, was of the orderof 60 C. The volume of the combustion products was therefore, reduced toabout one-quarter of its original volume at l,000 C., and this allowsthem to reach the flue through the [pipe 7 after traversing spaces 13and 4, which have a comparatively reduced cross section In addition, theheight of space 4 may also be reduced considerably. It was found that aheight of about 43 centimeters is ample to achieve a final cooling ofthe combustion products in this space, to a temperature not more than 2or 3 in excess of the temperature of the cold liquid entering by theconduit 6. The resulting thermal efficiency of the apparatus istherefore, almost equivalent to theoretical.

As in all heaters of the above type, the hot liquid is corrosive becauseof its direct contact with the combustion products which latter containacid anhydride substances. In many cases it may be of advantage to usethe hot liquid which leaves the heater through conduit 9 as a primaryliquid which surrenders its heat to a secondary liquid in a heatexchanger of corrosion resistant material and which reenters the heaterin a closed circuit through conduit 6. The secondary liquid would thenserve for transmitting the heat to a point of utilization It should bewell understood that the invention is by no means limited to theembodiment described and illustrated here by way of example andmodification thereto may not constitute a departure from the scope ofthe invention as defined in the appended claims.

I claim:

1. Heating apparatus comprising a vertical column, a combustion chamberin the lower half portion of said column defining an annular passagewaytherearound between the chamber and the column, said combustion chamberhaving a top and side walls which are closed, and a bottom which isopen, burner means disposed horizontally the combustion chamber at theupper portion thereof to discharge hot gases into said upper portionwhich then travel downwardly through the open bottom of said chamber andthen upwardly through said annular passageway towards the top of saidcolumn, inlet means at the top of the column for supply of a liquid tobe heated, the liquid flowing downwardly from said inlet means towardsthe bottom of the column, distribution means below said inlet means andabove said combustion chamber for distributing the liquid therein, saidcombustion gases flowing upwardly in the distribution meansandcontacting the downwardly flowing distributed liquid whereby heatexchange is effected therebetween, said liquid then flowing downwardlythrough said annular passageway for intense heating by contact with saidcombustion chamber and the combustion gases flowing upwardly in theannular passageway, and means at the bottom of the column for collectingthe heated liquid below the combustion chamber and for discharging saidliquid from the column said distribution means comprising a grid abovesaid combustion chamber, distributing elements on said grid, and adistributing tray above said distributing elements.

1. Heating apparatus comprising a vertical column, a combustion chamberin the lower half portion of said column defining an annular passagewaytherearound between the chamber and the column, said combustion chamberhaving a top and side walls which are closed, and a bottom which isopen, burner means disposed horizontally in the combustion chamber atthe upper portion thereof to discharge hot gases into said upper portionwhich then travel downwardly through the open bottom of said chamber Andthen upwardly through said annular passageway towards the top of saidcolumn, inlet means at the top of the column for supply of a liquid tobe heated, the liquid flowing downwardly from said inlet means towardsthe bottom of the column, distribution means below said inlet means andabove said combustion chamber for distributing the liquid therein, saidcombustion gases flowing upwardly in the distribution means andcontacting the downwardly flowing distributed liquid whereby heatexchange is effected therebetween, said liquid then flowing downwardlythrough said annular passageway for intense heating by contact with saidcombustion chamber and the combustion gases flowing upwardly in theannular passageway, and means at the bottom of the column for collectingthe heated liquid below the combustion chamber and for discharging saidliquid from the column said distribution means comprising a grid abovesaid combustion chamber, distributing elements on said grid, and adistributing tray above said distributing elements.